package cn.eyecool.uvc.util;
/*
 * libcommon
 * utility/helper classes for myself
 *
 * Copyright (c) 2014-2017 saki t_saki@serenegiant.com
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

public class FpsCounter {
    private int cnt, prevCnt;
    private long startTime, prevTime;
    private float fps, totalFps;

    public FpsCounter() {
        reset();
    }

    public synchronized FpsCounter reset() {
        cnt = prevCnt = 0;
        startTime = prevTime = Time.nanoTime() - 1;
        return this;
    }

    /**
     * フレームをカウント
     */
    public synchronized void count() {
        cnt++;
    }

    /**
     * FPSの値を更新, 1秒程度毎に呼び出す
     *
     * @return
     */
    public synchronized FpsCounter update() {
        final long t = Time.nanoTime();
        fps = (cnt - prevCnt) * 1000000000.0f / (t - prevTime);
        prevCnt = cnt;
        prevTime = t;
        totalFps = cnt * 1000000000.0f / (t - startTime);
        return this;
    }

    public synchronized float getFps() {
        return fps;
    }

    public synchronized float getTotalFps() {
        return totalFps;
    }
}
